FieldBench

Goodman

GSZ14

Heat pump · Single-stage HP · defrost board · contactor

Goodman single-stage heat pump. Contactor + dual cap + defrost control + reversing valve. O/B is board- and stat-specific — do not assume Carrier O-on-cool. Not GSZC18 communicating two-stage.

Not GSX16 (AC only — no RV, no defrost). Not GSZC18 / DZ20VC (communicating / inverter outdoor). Not a furnace 7-seg.

Walk this in Diagnose

This plate

Stages
Single-stage scroll · contactor
Defrost
Time/temp defrost board · outdoor coil sensor
RV
Energized per the board jumper / stat O or B

This board

Defrost control + contactor

  • Defrost board LEDs (if equipped) show defrost / fault. There is no ComfortBridge U4 on this outdoor.
  • Stuck in defrost = sensor or board. Never shifts = RV solenoid / stuck piston / no O/B.
  • Furnace E2 on the indoor IFC is not this board.

Sequence

  1. Y cool. Contactor in. RV position per O/B. Indoor on cool speed.
  2. Y+O/B heat. Contactor in, RV in heat. Indoor on heat-pump speed — not the gas-heat tap.
  3. Defrost. Board drives RV to cool and often energizes W for strip / furnace backup. Sensor open looks like never / always defrost.

Faults on this IFC

  • No Y

    Outdoor silent

    warn

    No 24 VAC at the contactor.

    • Y and C at the outdoor. Indoor actually calling.
    • Defrost board output to the contactor.
  • No shift

    RV / mode

    lockout

    Pressures do not swap with a heat/cool changeover.

    • O vs B at the stat and at the defrost board jumper. Goodman boards are not automatically Carrier O-on-cool.
    • RV solenoid 24 VAC during the commanded shift. Tap test / pressure swap.
  • Stuck defrost

    Defrost sensor / board

    warn

    Outdoor iced in heat, or runs cool-mode steam in heat all day.

    • Outdoor coil sensor ohms vs the defrost-board chart.
    • Board in test pins — do not leave it in forced defrost.
  • HPS / LPS

    Pressure

    lockout

    Airflow or charge.

    • Coil, fan, indoor airflow in heat (often the missed one).
    • Charge by SH/SC for this piston/TXV pair — not a GSZC18 weigh-in.

Workflows

No heat-pump heat, strips or furnace running

Outdoor quiet or running in the wrong mode.

  1. Confirm Y and O/B at the outdoor. A GR9S96 indoor still has to pass those 24V signals.
  2. Contactor in? Cap? Then pressures — are you in heat or cool?
  3. If it is cool-mode in a heat call, it is RV / O-B, not charge.
  4. Do not apply GSZC18 U4 / ComfortBridge to this defrost board.

Test points

O / B
Per THIS defrost board jumper and the stat. Do not assume Carrier O-on-cool.
Charge
SH piston / SC TXV. Not inverter weigh-in.

Gotchas

  • GSZB16 / GSZH5 are badge/SEER cousins — same contactor + defrost idea.
  • GSZC18 will never clear a U4 on this defrost board because this board has no data pair.

Related plates

  • goodman-gsx16 — AC-only sibling. No RV, no defrost.
  • goodman-gszc18 — Communicating / two-stage HP. U4 and data pair live there, not here.
  • goodman-gr9s96 — Common 24V indoor. Furnace EE-codes are not outdoor defrost.